Telephone-exchange system



Oct 27 1925 W. T. POWELL TELEPHONE EXCHANGE SYSTEI Filed Jan. 4, 1921 5 Sheets-Sheet 1 /m/e/rfar. W//lfred 7. Powe/I.

W. T. POWELL TELEPHONE EXCHANGE SYSTEI ou. 27, 192s. 1,559,372

Fl'ed Jan. 4. 1921 5 Sheets-31691; 2

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5 Sheets-Sheet 5 W. T. POWELL TELEPHONE EXCHANGE SYSTEM Filed Jan.*4, 1921 .w .MQ w@ RQ .wwf KQ H w Sh h, 3:; .n @s A. 3f. n.3?? en.: 2+ s in E u DI@ Naf 9L IIIA Illu D# 1071. NNN kth. MX@ .um NN NN www.. 2,... mm 0T2 n.5. An.. b @n n l@ 5x@ Oct. 27, 1925' oct. 27, 1925. 1,559,372

W. T. POWELL TELEIHONE EXCHANGE SYSTEM Filed-Jan. 4, 1921 5 Sheets-Sheet 4 N. T. PCWELL TELEPHONE EXCHANGE SYSTEI Filed Jan. 4, 1921 5 Sheets-Sheet 5 /m/enor.' W/hfred T. Pawe/l.

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vPatented Oct. 27, i925.

[UNITE STATES- Parar eric' WINFRED T. IPOVVELL, O'F ROCHESTER, NEW YORK,-ASSIGNOR TO WESTERN ELECTRIC COBIPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Application filed January 4, 1921. Serial No.v ft'l.

To all ic/icm, it 'may concern:

Be it known that I, VViNFni-JD. T. POWELL, a citizen of theUnited States of America, residing at Rochester, in the county of `Monroe,

phone-Exchange Systems, ofavhich the following is a fiill, clear, concise, and exact `fdescri'ption.

This invention. relates to telephone exchange systems, and more particularly, to telephone systems' in which connections are established by means Aof automatic switches under the control of calling subscribers and in which telephone service is charged by means of a coin device at the siibsciibers substation.

In systems of this general character, it is Y the usual practice to control the calling subscribers coin device to charge for the service by means of controlling mechanism at the central office which causes the deposited coin to'be collected if thevestablished con neet-ion is successful, that is, if the called -5 subscriber responds, and to refund the coin if the connection is unsuccessful.

Inorde-r to effect .a saving in apparatus it has been proposed to provide controlling mechanism for controlling subscribers service charging devices which is common to a plurality of groups of automaticswitches and which, therefore, may 'be associated with any one of a plurality of established connections. y

are power-driven under the control of a register. sender Aat the centra-lollice, the sender is associated with the automatic switches employed to establish a connection, through the medium of a sender switch which func- Ations immediately following the initiation of a call. As soon as a connection, has been established through the functioning ofthe tate of New York, have invented cer-. tain new and useful Improvements in Tele-- In systems in whichthe automatic'switches scribei-7s service charging devices at all stages of initiated connections and to thus avoid the necessity of employing auxiliary controlling mechanism.

'.lo accomplishthis result since at the time it 1s desirable to charge for the service following the completion ot a connection, the sender has been disassociat'ed from the con` ncction, it is necessary to temporarily reas-` sociate an office sender with the established f'zonnection.v In the system herein disclosed the sender is reassociated with the connecnisni and method for controllingsubscribers service charging devices.

It is more specifically an object of this intion immediately following .the restoration vcn'tion to provide controlling mechanism for controlling service charging devices associated with an oflice sender and'to -'profA vide a singlemeans for associating. the office sender and associatedcontrolling mechanisin with an established connection to control the charging device.

A feature of the vinvention residesin the provision of an oilice sender common to a' plurality of groups of auto-matic switches` for controlling` the switches .to establish connections between subscribers lines and pro-' vided with mechanism for controlling service charging devices on calling subscribers lines at all stages in the establishment of connections.

A further feature resides in the provision of means for associating a. common olice sender with a subscriber-s district selector switch for controlling the establishmentof a desired connection, for disconnecting the sender upon the completion of the establishent of the connection and for reassociating a sender and associated controlling mechanism with an established connection upon.A the initiation of the release of the connection for collecting a coin deposited in the subscribers service charging device, or for refunding the coin dependent upon the success of the established connection.

Such other features as are contemplated by the present invention will become more apparent from the following description and thel a-ppendedz o'lfirns.'

invention.; In the drawings Figs. lto-:vne' elusive: illustrate' dagrammatiealy so. much of the circuits and apparatus of a telephone exchange system as are necessary to (arribo-dj' the features of the presentinvention.

Fig. 1 shows a calling subs'cribers'line togetherwith a vdistribiflting. switch individual to such line, Fig. Qi'slioi-'vfsx` a district Seletor sritcliandl a' sentieri finden su itcli together with the circuits and controlligrmelianisni Origine @nenas effan...iacaiagggeiecwfnach,

final1 sleetor swit'clradzi calle subscriber@ 1ii i e ;.lig 4 'Shewsthe circuits andapparatus of "tlie seriiic'e. Charging" controlling inec'hai o'ankotleeseiider with Which-the cont'r'ol ling.t niechanisir'i; of; Eig'. 44s permanently.

ass'Ocitedalid'F dis-a illus-trat- 1ri'g;'the inannrnijwliich the'seifer'al figures close a' completeigaization of'tlie circuits invgolred in the invention,

The selector sif'itchesdisclosed in Figs. 2 aiidz"niayhbefofptlie type disclosedin the patent to E. B3 Craft' aIidJl N. Reynolds 1,123,696" issue-d January-5,1915: In Fig. 3`

only the brushes of tle incoiinv and final selector sivit'cl'eskaiid Vcertain ofthe .control- For a.

ling circuits have. been di'sclsd` full disclosure of,thesaswitchesand assopatent te Mins, No; 1504261, issued Auguseiaiisai;

The sender diagramma-tical@ .disclosed inV 'Figi 5..-1nafy. be oi thetypedisclsedin the patenti issued' to H lilills hereiilbefore referred to, .only suclipoitionsofa the. sender being' diselsed'lieiein as are'necessary to :in understanding; oir the inifeiitirn, The se.-

. quence sri-'itch' Canis.disclsediiiithintlie dtL dit' ' tedV rectangle.. are` associated.. in, the` wellknoivninannerwith a--seqilence switcliipoiverl magnet (not shown), andare erniiloyedto control certain circuits of. the-sender` In tlie lou-'er right-hand corner of Fig. 5., a reg..- ister.. steering switch isdisclsed which is -instrumental inf associating, the iinplsing. circuitiextending tothe subscriberis line successively ivitlia' plurality o'ffstep-by-step reg-V isters (not shown) for egisteiingtlie ksevT eral? digits of the designation of a desired line. For a full disclosure ofthe circuit'sof the sender andthe' manner in which they',v`

function, reference may be had to the-,aforementioned patent: issued to. E. H. Mills. Detailed description of operation..

The manner in which the' syst-ein is organized will best be presez'ited in connection with aA description of its inode of operation. It will be assumed that the subscriber at THe: -iniientiior'i will nonV b'e described in connection with one specific embodiment of the genus'of' the` Ofi." relay Bel-ay enelgies'in this' circuit and-v dost-sa.' circuit for t-h'e ste "ping, magnet' 1,057', ri'hich circuit: irajf be" 'raced from Battery, throughYA the'widng and: an mature contacts oi magnet 105,'condctor 106,v the lowrr'nofst armature: an'dback c 'ontact of relay 102, the" right-Hand: armature anlfon't Contact'"ofVi relayv lLfcodctor 10T' and' thence` to' ground. tirifoug'l the' Wiper 108 and the: normali' terminal: ofthe b'anl to' wlficlithis Wiper has access.` The magnet L' 105 upon energizing in tlii's circuit' adifair'ces the wipers 108, 109. 110, ,111, 112 aiid1'1'3fto tlie second terminals' oft-lie' resfpectiife banks. to which they have. access'. Als the'A secondv ter'minalvwliich" Wiper 108niv'engage's is permanently connected' tb ,gi/olind,r magnet.

105l continues lto steptlie Wipers'tb the third set of tefrrniriails leadingZ to the first of the' group of trunks to which the switch 100 has access;

rf" the `first ,trunk fthegroupj is. busyA uierfe; will be a; ground @central on nietes-t;

ternnnaitlereof appearing inthe lower'most banl of "the SWitchfafnd: the switohuw'illithere'- fore continue steppihgfuntilalidl A,liriinli is' find''on t'lie .test trmiiial'of'wliioh battery. fot'enftial appears.vr l/Vlien tllis battery pot/'en' i'all is encountered, a circuit is. closed from battery, through the rightliiandjcon'- tants loit' earn 202' at'A the ,district` selector Switch to' .winehthe. Hfst idle trunk extends, through" the.' inner left'fli'and'' armature and back Contact' of'slee'i'fe relay. 226, testi.cfondiiL tor i111",v wiper 108,`v conduct-'or .10?, the left,- hand armature andv front Contact' and leftles hand; winding of relayv 101-7 eend-ucm 115 and'thence to ground ythrough bothwindings offrelay 102 Relay 101'y is inaiiainedenergizedaiid relay 102'energizesin' this circuit.

The energilation of' relay 102'fope'njs the' circuit ofthe. stepping magnet 105j atits lowerniost aiinture' and'b'ack Contact" and at. `its upper armature' and front contact and intermediate. armature and front contact this' re.- iy extendgtheconduetiers"103 and, 10410-15 the.subseribensxliiie to the'rvip'ers 1'11 and 11`3'of'the sri/itoli'll() and tlie'nce to the trunk conductors 116l and 11.7"leading to the. selected.dist`ri`ct selector. Relay 102A at' its lower intermediate armature and front contact h closes al circuit extending through the lefthand Winding of sleeve relay 226, through the normal contacts of the lett-hand armature ot slow releasing relay 227` the lower right-hand contact o1 cam 203 (1 to 21/2), sleeve conductor 118, wiper 109, conductor 120, the lower intermediate armature and front Contact ot relay 102 and thence to ground through the upper Winding ot' rela;v 102. The sleeve relay 226 of the distrirt selector switch energizes in this circuit.

For making` the calling subscribers line busy to all calls incoming thereto, battery potential is connected to the multiples ot test terminal 121 appearing in the bangs ot all inal selector switches having access 'to this line, over conductor 122, wiper 110 and the ott-normal segment 1221 to battery. )Viper 112 throilgh the grounded olt--norinal segznent 124 prepares a circuit extending; over conductor 125 preparatory to restoring` the tinder switch 100 to normal when relay 102 becomes deenergized upon the termination ot the connection.

Upon the energization oi relay 22o, a circuit is established for control relay 38 ot the district selector switch 2530. which eircuit extends troni battery through the righthand winding; of this relay` the upper contacts of cam 201, the right-hand armature and front contact of relay :220 and thence to ground tl'irough the upper right-hand contact ot cain 205 (17 to 15). At its inner lett-hand armature and front contactr` relay 220 connects ground potential to the test conductor 114 of the selected trunk to mark the trunk busy to other line switches and at the back contact ot this armature disconnects the source ot battery potential which up to the time the selector switch was seized marked the selector switch as idle. rlhe l ckingr circuit ot' relay 101 is now opened and the relay deenergizcs.

l\elay Q28 upon energizingij closes a circuit tor drivinzc` the sequence switch of the dist riet selector out of normal position 1 into position 2, this circuit extending' from hat`A lcry through the magnet winding ot sequence switch Q00, the lower right-hand contact ot' cani i200 (1), the inne' rightdiand armature and front contact ot relay and thence to ground at the upper right-hand contact ot cani 20T (T1/ 1 to t). The sequence switch magnet eiieurizes in this circuit and under the control ot master cani 01 drives the sequence switch into position i, in which position a circuit is closed Vtroni battery through the lett-hand friiulinj v ot relay 22T and thence to ground through the upper lefthand contact ot cani 205 (2 to l1). Relay 252i' upon energizing closes a holding` circuit tor relay Lo extendingv through the lefthand Winding ot relay Q20, the alternate coir tarts ot' the letthand armature ot relay 20T and thence to the sleeve conductor 11S, over the upper right-hand contact of cani 9053 (1% to 10), this circuit being maintained through position 16 of the sequence switch, or until relay 227 becomes deenergized. Upon reaching position Q, the sequence switch connects a new busy ground to the test.conductor 114 at the lower left-hand contact otl cani 20th which busy ground is maintained through position '181/1 ot the ,sequence switch.

oiled/0a of an, fl/c .scholen del lin parallel and thence to ground at the upper lett-hainl contact otl cani 200 to 11).

clays 30 and '21"1 do not energize at, this i t liowcrcr, since their windings are shouted by Aaround connected through the armature ot relay 228.

s soon as eminence switch 200 leaves positi-ni L the initial energizinev circuit ot getty zu is opcned at the upper contacts of cani 211i. but this` relay remains locked over a circuit extending trom battery through its lett-hand winding. its lett-hand armature and trout contact. the lower right-hand contact ot cani Q (l to t3)i the lower lett-hand contact ot cani 211 (p1 to ft/), the outer letthand armature and ront contact ot relay "ftf, test wiper 2231 ot the sender linder switch and to ground on husr terniii'ials ol" the haul; over l ich this wiper moves. ,1s sooiu howeycrr1 :is an idle sender mechanism is tound. tlul wiper 2531 niii [ind no Aground potential on the terminal corrcsptnidiugr to such idle sendcr nlcclianisin and the control relay will thereupon deenerciz". opening, at' its` inner right-hand arinaturc and front Contact the circuit extending through the stehiingj magnet 2:50 and cios ing at its inner right-hand armature and laici; contact a circuit tor driving' sequence switch 200 out ot' petition l and into posiv This circuit may bc traced troni 11H11 i). battery through tlu nae'nct windingl ot sefgucnce switch :300. the upper lett-hand con tact ot' cani 200 (2). the inner rinhtdiand armature and lr nl; contact ot relay 22o and thence to ground at the ri` "ithand contact cani T.

)is soon as: relay :22S dcenergizes. the shunt alound thc indiana ot' relays :250 and 241- is aired at the inner right-hand armature ni contact ot relay 272511 and relays lll thereupon energize in series with magnet 229, the current flowing through this circuit, however, not being sutticient to cause the energization of the inagnet. Relay 230 upon energizing closes a circuit extending trom ground through the inner right-hand armature and tront contact ot this relay. over wiper 231` and the terminal upon which it is resting, conductor 500 and thenct` to battery through the left,- hand Winding` ot ditierential relay 501. Relay 501 energi'fies in this circuit and closes a circuit `t'or advancing' the time n'ieasnre switch TM out ot its normal position. This circuiti may be traced from battery throuejh the Winding ot stepping nurgnet 502, wiper 503 and the normal terminal ot' the bank with which it is associated, interrupter 501, outer leftehand armature and back Contact of reiay 505 and thence to ground at the armature and front contact ot' relay 501. Stepping magnet 502 advances the wipers ot the time measure switch into position 2 under the control ot' interrnpter 5011 for measuring oit a suitable time interval betore relay 505 becomes energized to connect the calling subscribers line with the registers oi' the sender.

As soon as the time measure switch reaches position 2 a circuit is established relay 505 which may be traced 'from battery through the winding ot this relay, banlt terminal 505, wiper 507 and thence to ground. Relay 505 energizing in this circuit closes a locking circuit tor itself extending through its winding., its intermediate lett-hand armature and trout contact and thence to ground at the armature and tront contact ot relay 501. At the .back contact ot' its outer lett-hand armature, relay 505 opens the circuit previously traced through the stepping magnet 502 and closes a new stepping circuit which may be traced trom battery through the winding ot magnet 502, the arnniture and back contact ot this magnet, wiper 50S, the second position terminal 509 with which the wiper 500 is now in engagement, the outer lett-hand arnmture and t'ront contact ot relay and thence to ground at the armature and trout contact ot relay 501. Stepping magnet 502 is now energized in this circuit and by means ot its own seit-interrupting armature contact adyances the wipers ot'y time measure switch 'Hl to position 0. in which position the circuit ot magnet 502 is opened at wiper 500. As soon as the time measure switch leaves its normal position. busy ground potential is applied to the test conductor 500 multipled into the bank terminals ot all sender tinder switches having` access to the seized sender. This busy potential is applied to conductor 500 over a circuit which may be traced from ground through Wiper 510, the ott-normal terminals ot' bank 511, the right-hand Winding of relay 501 and thence to test conductor Tai tor 500. The right-hand Winding of relay 501 being shunted at this time is without effect.

Relay 505 upon energizingV also closes an impulsing circuit for associ-ating the registers ot the sender with the calling subscriber"s line, which may be traced from battery through the Winding' ot stepping relay 512. conductor 513 the outer lett-hand armature and back contactof relay-100, the outer letthand armature. and back Contact ot relay 101, conductor 5105*),A the right-hand armature and trout contact of relay 505, conductor 514, wiper 236, the inner left-hand arm-ature and front contact ot relay 230, conductor 285. the lower lett-hand contact ot cam 2121, the Winding; ot relay 234, trunk conductor 116, wiper 111 of switch 100, the innermost lower armature and front contact ot relay 102, conductor 103 through the calling subscribers sending dial S, conductor 104, the upper armature and front contact ot relay 102,? wiper 118, trunk conductor 11T. the lower le't'thand Contact of cam 2.1iy conductor 233, the outer lett-hand ar inf 1 ire and Afront Contact of relay 230` wiper 2232, conductor 515, the inner letthand armature and front Contact ot relay 505, conductor 402, theouter right-hand armature and baci( contact ot relay L101 the outer right-hand armature and back contact ot' relay 400, conductor 404 and thence to ground through the Winding' ot retardav tion coil 510. llheste'pping relay 512 energizes in this circuit and at its righthand arnmtnre and front contact closes a circuit tor the slow releasing relay 517. This circuit extending from battery through the windingg` of relay 517 and thence to ground through the right-hand armature and front contact ot relay 512.

Upon the initial energization ot relay 501` a circuit was also established tor initiating the operation of the monitoring time measure switch M. The starting circuit tor this switch may be traced 'from battery through the winding' of starting relay 105` the normally closed contactsI associated with its invner lett-hand armature. wiper 400 ot the switch lVl and the normal bank terminal upon which it is resting', conductor 4707. thence to ground at the armature and 'front contact of relay 501. Relay 105 euery' in this circuit establishes a locking` circuit tor itselt independent ot the wiper 400 which may be traced through its winding` the malte contact ot its inner lett-hand armature. conductor 408 and thence to ground on conductor 407. At its intermediate right-hand armature, relay 405 establishes a circuit tor slow-to1elease relay 400 which may be traced from ground through the intermediate right-hand armature and tront contact ot' relay 405, the inner lett-hand armature and back contact of relay L110, wiper L177, the normal bank terminal upon lia! which it is resting` the Winding of relay 409, conductor y-111 and to battery through the right-hand armature and back contact of the coin translator register relay 518. Iielay ltl) upon eneigizingl closes a locking circuit tor itself extending from conductor 411, through its winding. its lett-hand armature and front contact` the outer righthand armature and back contact ot coin collection relay 112, conductor 113. the armature and back contact of coin test relay 114, the inner lett-hand armature and back contact ot relay L15 and thence to ground at'. the outer right-halnl armature and Jfront contact of relay 405. Art its right-hand arlnature and JfrontI contact relay 409 establishes a circuit 4for relay H0 which may be traced trom battery on conductor r111. through the winding of relay 410 and thence to ground at the right-hand armature and front contact o't relay 400 and a circuit tor relay 410 which may be traced Vtrom battery through the right-hand winding of relay 410, wiper 417 and the normal bank terminal upon which the wiper is resting and thence to ground at the righthand armature and 'front contact ot relay 400. The energization otl relay 116 is without etlect at this time. Vlelay -1-10 upon energizing establishes a stepping circuit for the stepping magnet 415` ot' the switch v which may be traced trom battery through the Winding and armature contact ot magnet 418, the right-hand armature and trout contact of relay 410, wiper y-117 and the normal bank terminal upon which it is resting and thence. to ground at the right-hand armature and front contact ot' relay 40S). Stepping magnet 41S advances the wipers ot' switch M one step when the energizing circuit ot relay y-110 is opened at switch wiper 117 and the previously traced circuit through the winding ot stepping magnet -l1@ is opened at the armature contact ot relay 110, lith relay -310 deenergized and switch M in position 1, a new driving circuit is closed tor the switch )I through the winding of stepping magnet 410 and the slow interrnpter 110 which may be traced from battery. through the winding ot magnet #118, right-hand arn'lature and back contact ot relay e110, interrupter -110` the inner lett-hand larmature and back contact of rela 1.' f. l. the No. 1 terminal in the bank with which wiper lli' is associated. wiper 47T. the inner left-hand armature and baci; contact ot relay l110 and thence to grlfiund at the intermediate right-hand armature and trout contact ot relay -t-(t.

linder the influence ot the slow interruptor 110. switch M is advanced into position 3 nxeasuring oli' time suli'icient to enable the calling subscriber to dial the tirstdigit. If the calling subscrilfrer fails to dial the iirst digi! within the time measured by the adyance of switch M to position 3, a circuit is established for displaying a signal on the sender monitoring lamp 421, which circuit may be traced from grounded battery through the lamp 421. the outer left-hand armature and back contact ot relay 415, bank terminal --QZ, wiper 423, the outer lefthand armature and back contact of relay L10 and thence to ground at the intermediate right-hand armature and front Contact ot relay 405. At the same time a signal is displayed by the auxiliary pilot lamp 424, the lamp 421, being illuminated in the circuit which may be traced through the right-hand armature and back contact ot` relay 420, contact terminal 425, wiper 47T, the inner lefthand armature and back contact ot relay 410 and thence to ground at the intermediate right-hand armature and front contact ot relay 405. The monitoring operator noting the illumination of lamps 421 and 424 takes the necessary steps to ascertain the trouble on the calling line, or the reason why the calling subscriber has failed to commence dialing.

Assuming that the calling subscriber does proceed to dial the tirst digit of the number ot the desired connection Within the specitied time interval, and further, assuming that the subscriber desires a connection with a subscriber-ls line B which is listed in the directory as L I S penard 9532 and that thc calling line is to be reached through a district selector switch Q50, an incoming selector switch 300 and a tinal selector switch 350, the subscriber proceeds to dial three letters corresponding to the otiice designation of the desired line and then dials four digits representing the number ot' the line in such office. In the case assumed the calling subscriber will dial the three letters L I S and will then dial the numerals The three letters which represent the ottice code will in the manner fully set forth in the patent issued to E. H. l\Iills hereinbe- 'tore referred to, cause the setting of the code registers ot the sender tor controlling the setting of the district selector switch for determining the adjustment of the circuit of the sender and for determining the positioning of the sequence switch of the district selector switch for talking selection.

In response to the first impulse dialed by the calling subscriber in accordance With the tirst letter of the ollice designation, the stepping relay 512 deenergizes and closes a circuit for the stepping magnet not shown) ot the .first code register, which stepping circuit may be traced in part from ground through the right-hand armature and back contact ot' relay 512, the right-hand armature and front contact of relay 517, the winding of slow-to-release relay 519, wiper 520 land the normal position contact upon lay 228 ot the district selector switch and the stepping relay 530 of the otlice sender are energized in tlns circuit.

[ratei/,sion of' connection, t0 ctt/tert Hm'.

Relay upon energizing closes a circuit tor driving sequence switch 20() ot the district selector' out ot position l and into position l. This circuit extends troni battery through the magnet winding ot 20th the lower right-hand contact oft cam Ltlt t3). the inner right-hand armature and trout contact ot relay .228 and thence to ground at the right-hand contact olE cam 20T (T1/ to lith the district selector sequence switch E200 in position L'l'. a circuit is now close-:l tor the updrive magnet 23S which extends trom grounded battery through the winding ot magnet 238. the right-hand contact ot cam S (l) and thence to ground through the inner right-hand armature and front tontact ot relay 20S and the righthand contact ot cam 20T. Magnet 23R upon energizing presses the depending portion ot the switch sha't't 239 against the constantly rotating updrive drum 24U. thereby causing the upward movement ot' the switch shaft. Upon the movement ot the` sequence switch 2U() out ot position 4, the initial energizing circuit ot relay which extends through its lett-hand winding is opened at the lower lett-hand Contact ot cam 210. but a locking circuit tor relay 228 is closed at this time through its lett-hand winding` its lett-hand armature and trout contact and to the t'uudamental circuit previously traced. through the lower right-hand contact ot' cam Q10 (i a) c).

\s the switch shaft 239 approaches its tirst brush selection position. the brush 2st-l enga the first ctniducting portion ot the cnnnnutator segment Q42 and a shunt circuit is establisl'led around the winding ot thc sender .stepping relay 53() which may be traf-ed .from battery through the lett-hand winding. lett-hand armature and trout contact ot' relay 22S. the lower right-hand contact ot cani 2l()` the upper lett-hand contact oll relay :lll (3S/f, to 4). conductor 243, Segment Lft-l1). lu'ush Q'll and thence to ground at the lower contact ot cam Q09 t9 to T). Relay 22S is maintained energized over the shunt circuit. but sender stepping relay 530 is caused to deenergize. s the switch shalt W tontinues in its upward movement the brush 2li engages an insulating portion ot the fegment 242 and the shunt circuit previously traced is opened, whereby the sender stepping relay 53() is again energized. Thus, during the upward movement of the switch shat'ti the sender stepping relay 530 is intermittently energized and deenergized.

Vllnder the assumption that the calling subscriber has dialed the code L l S` a circuit is established upon the tirst energization ot stepping relay 530, in the well-known manner, tor the No. 2 counting relay 535 which circuit may be traced in part troni battery through the winding ot relay 535. the armature and back contact ot the No. i2 counting relay 53o. thence over the lead 53T and to ground through the armature and t'ront contact ot' relay 53). Counting relay 535 upon energizing in this circuit closes a locking circuit t'or itselt extending troni battery through the winding ot relay 535. the winding ci' relay 53o. the armature and 'trout coutact ot relay 535 a nd thence to ground at the` contact ot sender sequence switch cam 538 (Y). 'l'he upper counting relay 536 does not energize until stepping relay 53() deenergizes at the time the brush 2l-1 otl the district sele tor en gnige-A the first conducting portion ot' segment pon the energization ot relay 53th lead 53T is extended through the armature and trent contact ot relay 536, the armature and bach contact ot the No. l counting relayv 53S) and to battery through Athe winning otI the No. l counting relay 540. l'pon the second energization ot stepping 52W. relay 5t() becomes energized and tochup through the winding otl relay 539 and in reaponae to the next energization ot. stepping reiay 530. the No. 0 counting relay 511 becomes energized. and locks up through the winding ot' the o. 0 counting relay 54;. lpon the next deenergization of steprelay 530. the 0 counting relay 542 enn .e-r in parallel with relay 532. Upon the energii/ation ot counting relay 542, a circuit is established tor advancing the sender sequence switch 52T out ot position 2 and into position l. This circuit extends trom battery through the magnet winding of Seoucnce switch 52T. the contact ot sequence switch cam 5 l (i2). and thence to ground at thi` arnnttnrc and trout contact ot' relayY 51;). .is soon as the sequence switch leaves position 2. thc loclcing circuits, ot the energized counting relays are opened at the contact ol' cani 53S.

Upon the energization ot relay 53;" the fundamental circuit is opened at the armature and back contact ot this relay and soon thereafter as the brush Zll ot the district selector engages the next insulating portion ot the comnintator segment 242, relay 22S ot the district selector deenergizes. closing a circuit tor driving the district selector sequence switch Qtltl out ot position l and into position 5. This circuit extends4 trom battery through the magnet; winding otsequence switch Q00. the upper lett-hand contact' of cam Q06 (l). thc inner righthand armature and back contact ot relay Q28 and thence to ground at the right-hand contact ot cam Q07. As soon as relay 22S deenergizes. the circuit previously traced through the updrive magnet 238 is opened at the inner right-hand arn'iature and bach contract of relay 228 and the upward movelnent of the switch shaft is arrested. lith sequence switch 20() of the district selector in position 5 and the sender sequence switch 52T in position l. the fundamental circuit previously traced is airain established and relays 228 and 5230 again energize. Relayv 228 upon energizing' causes the movement of the district selector seruieuce switch 20() from position 5 into position (l, the initial energizing' circuit of relay being opened as previously described at the lower leithand contact of cam 2l() as soon as the sc quence switch leaves position 5. Relay 2:28 however. remains energized over the idaniental circuit through its left-hand windlng` left-hand armature and front contact and the lower right-hand contact of cani 210.

Duringthe brush selection moveiuut of the district selector from the time the sev qucnce switch reaches position il. a circuit is estahlished through the righchand winding of the differential relay 22T. the upper contact of am 214, the right-hand armature and front contact of relay which euergized in parallel with relay 22 l. the low" er contact of cani 215 (3 to 1W, wiper 2li, conductor 544, the right-hand armature and hack contact of advance relay 545, resistant:l element 545 and thence to ground at the contact ot cam 5M. The resistance element 546 included in this circuit is such that the current flowinfrT in the rightdiand winding of relay 22 i is not sufficient to cause the ditterential relay 22T to become iuilmlanced. and relay 227 therefore remains energized over the previously traced initial energizing circuit. The circuit just traced is malin tained until the district selector sefpiencel switch leaves position l following' the conipletion oll the setting of all the selector switches and is established for n 11m-DOS@ which will hereinafter be described. Upon reachingr iosition G. the circuit previously traced for the updrive magnet 23S is aa'ain established through the upper right-hand contact of cain 208 (6) and the inner i'i; 'lit hand armature and front contact oi' r( y 228, and in the manner previously descrihed, the switch shaft 239 is again driven upwardly. Since at this time the tripping' spindle has heen rotated by the trippine magnet 227.y which was energized in position of sequence switch 200 over a circuit er,itei'ifliiif,r

from battery through the windingl ot' mag t 2st? and to ground through the lower zi vhthand contact of earn 205 (5 to 7), the third set of brushes is now tripped upon the initial upward movement. of the switch shaft and during the continued upward movement of the shaft the brushes travel over the bank with which they are associated. A the switch shaft approaches its first group selection position, the brush 248 engages the first metallic portion of the group selection segment 249 of the eonnnutator and a circuit is closed in shunt of the winding of the sender stepping relay 530, which may be traced froni lia'ttery through the lefthand winding', left-hand armature and front contact of relay 22S, right-hand contacts of cam 210, segment 2li), brush 2&8 and thence to gz'round at the lower contact of cani 209. llelay 22T is maintained energized over this circuit, but sender stepping relay 530 beecnies deenergized. As the switch shaft continues in its upward movement and the brush engages the first insulating portion of touunutator segment 2479. the shunt circuit is opened and sender stepping relay 5530 again energizes. ln this manner Cliriim` the upward movement of the switch shaft in its ,L'roun selection movement` the .fender stepping' relay 523i) intermittently encrp'izcs and deenergizes.

1t will lie assumed that the code which the calling' subscriber has dialed has so set the registers of the sender as to prepare a circuit for the No. (l counting relay 541 upon the lirst energixation ofthe sender steplinfa' relay 530 in the well-known manner. ythus. upon the l'irst deenergization of steppine' relay' Bill). the No. 0 countingr relay Y euergizes in parallel with relay and at its armature and front contact closes the previously traced circuit for advancing sender sequence switch 52T out of position l into position 6. Upon leavingy position Ll, the locking circuit of relays 541 and 542 is opened at the contact of cam 53S. Relay m' upon energizing opens the fundamental Jul circuit at its armature and back contact thereby causing the deenereization of relayY 228 of the district selector switch as soon as the brush 2&8 engages the next insulating' portion of segment 249.

Relay 22u upon deenern'izingr opens at its inner right-hand armature and front coutact the previously traced circuit of the updrive magnet 23S, thereby arresting the upward nioveuicnt of the switch shaft for positioning' the tripped set ot' brushes beneath the first `group ol' terminals in the bank. At its inner right-hand armature and hack contact, relay 228 closes the previously traced circuit for driving sequence switch out of position 5 and into poistion 7. In position T, relay energizes over a circuit extendina' from battery through its right-hand winding, the upper contacts of cani -l, the right-hand armature and front contact of relay 225 and thence to ground at the upper right-hand contact of cain 205 (17 to 15). Relay 228 upon energizing; closes a circuit for driving' sequence switch 200 out of position 7 and into position 8, which circuit may be traced from battery through the magnet winding of the sequence switch, the lower right-hand contact llll lil() 'at the of cam 206, the inner right-hand armature and front contact ot relay 228, the upper left-hand contact of cam 207 (7 to 8) and thence t0 ground at the right-hand armature and front Contact ot relay 22'?.

As soon as sequence switch 200 leaves posi tion T, the initial energizing circuit ot relay 228 is opened at the contact ot cani 204, but relay 22S locks up orer a circuit extending trom battery through its lettwhand winding, its lett-hand armature and trout contact, the upper lett-hand and lower righthand contacts ot' cani 12in, the outer righthan-fl arm tin-e and troni contact of relay the lower contact ot cani 224 to the test hrueh 252, and it' the first tr-ik ot the selected group is lousy to nnni at the test terminal 2.2i) ol' .auch busy trunit. lipon reaching position H with relaxv 22h energized, the previously traced circuit, tor the npdrive magnet 23H is established and llnmagnet 23H again drives` the switch shall up\.ai'dly in search ol' an idle truuk in thc selected group. sito long afi the test brush 252 encounters flic terminals o't lvusy 'rnnlis the relay 225* remains locked up. lv'hen, however, an idie truul( is encountered, which. it will he assuuied` is the is the coniiziutat or brush 270 and to freund trunk terminatingl in the terminalsy 255. 25o

as the brushes and 250 have been tered, relay 22S remains` locked up orer a x 21T, the brush centering segment 200, hrnsli contact ot relay 22S and thence :o

magnet 233 is open-afd at the inner right-hand el and i circuit is contact ot relay ground ps 251. ofcrilow se;` r

` and lower lett-hand contacts ot cam fit1.

extending from battery through its rightand thence to ground at the armature and and the locking circuit ot relay 22H is opened and relay 225 deenergnces, as soon properly centered on the bank terminals 2535, 256 and 25T. Until the brushes are so cencircuit extending' through it"y r winding. the rightdisiml contact, it cani 201, the upper lett-hand eontzict oi cam 208, the inner right-hand armature :ind Ytront lrcuni! at the right-hand contact ot rain 20`. Upon deenergizing, the circuit oi the npdrire armature and fro-:it contact ot reiay the upward iioieinent ot the switch i ,.,y arrest i inner r l nd arnifztuie r 'tor drlur switch 200 out tlon 9. tpvi tipici ot te trunli over through the upper i"`hth1n\l Relay again energizes when sequence switch 200 reaches position 0 over the circuit hand winding, the upper contacts et cam 21T, the upper contact ot cani 218 (l to 10) At'ront contact ofrelaj.Y 201. Relay 201 is at this time energized over a circuit extending trom battery, through its Winding, the left-hand contacts of cani 215, wiper 245 of sender linder SF, thence to ground at the contact ot sequence switch cam 547 over the circuit previously traced. Relay 228 upon energizing closes the previously traced circuit through its inner right-hand armature and trout contact tor driving' sequence switch 200 out ot position 0 and into position 10, in which position the fundamental circuit is extended through the contacts ot' sequence switch cams 215) and 220, through brushes` and 250, respectively, to the line relay ot the incoming selector switch 300.

Upon the extension of the fundamental circuit to the incoming selector switch, a circuit is closed from battery, through the right-hand winding of relay 301, the righthand contacts of cam 302, associated with the sequence switch (not shown) of the incoming selector switch, conductor 303, resistance element 304, the upper contact ot' cam 305, trunk conductor` G, bank terminal 257, brush 259, the upper letthand and lower right-hand contacts ol cam 220` conductor 262, the outer right-hand armature and front contact of relay 230, wiper 23T, conductor 528, the armature and hack contact ot relay 529, sender stepping relay 530, the winding of overflow relay 531, the armature and back contact of relay 532, the upper contact ot sequence switch cam 533 (6), conductor 548, wiper 263, the left-hand armature and front contact of relay 244, conductor 264, the lower right-hand and upper lett-hand contacts of cam 219, brush 258 and bank terminal 256 of the district selector 250, trunk conductor 307, the lower contact of cam 308, resistance element 300 and thence to ground at the lower contact of cani 310 (1 to 8). Relay 301 energizes in this circuit and at its armature and front contact closes a locking circuit for itseltextending through its right-hand winding, lower contacts ot sequence switch cam 302, the armature and trout contact of relay 301, the contacts ot sequence switch cani 311, thence as previously traced over the fundamental cir ait and in the well-known mauner establishes a circuit for advancing the switch shaitt ot the incoming selector switch in its brush selection movement. During the upward movement of the switch shaft, the sonder stepping relay 530 is intermittently energized and deenergized in the wellltnown manner, to energize and lock up Successive pairs of counting relays. Assuming that the calling scail'iscrihcr has at this time dialed the thousands digit 9 and has, theretore, set the thousands register in position 9, tive pairs of counting relays will be energized and locked up in succession and when the 0 counting relay 542 heroines energized, the sequence switch 527 of the sender will be advanced out of position 6 if.. if)

and into position 8 in the well-known manner. Relay 532 which energizes in parallel with thtl 0 countingY relaj.' 512 opens; the tuiulamental circuit at its armature and back contact and relay L01 at the incoming selector switch deenergizcs, therehy arrestingl the upward movement ot the switch shaft ot the incomine selector 300. Following thc deenergization ot relay 301, the sequence switch (not shown) ot the incoming selector' advances to such a position as to control the selector switch in its group selection movement.

Upon the termination ot the hrufh r-clcction movement ot the switch shatt ct the incomingr selector switch, the triping' in net (not shown) ct thc iieo""ng eelt-t r`per preparatin'y to triiipin ed set et hrnshes np3 a suhseouent t i@ inote'zniit the tch in the viell-lnoun www switch ot the ti' n l il 7Aelected set fit' l ffly c t, Eicletimine/l gironi "t' lra tinals' in accordance with the setiifr et the th i1- anl hundreds re "ters oi' th ttlll 2` r.

iwi i the completion ot the {tref-ip selection i nein-.lint ot the icc-Nin@ f-`f'ltt'tf"-' part trom ontact lower contact ot cani 30T. thence as4 iircyif sender and throi 1li the win-linx et' winter stepping reiav t" or Sltt. tAA

resistance eleA and returning' ov ier contact' ot e; 1 i. 304-a conductor 303, the

upper contact or cani (Sl. hrush 31,3 ot the in-f'on'iin selector switch and thence throoh the controlling relay (not shown) ol the tinal selector switch to hatterv in the well-known inanncr. A holdingr circuit also established at this time tor relay 301 which naiv lne traccd 'troie fggxwrfinleil hit' through the winding of relay 301, the lower contacts ot cam 302, armature and iront contact ot relay 301, the lower contact ot cani 314 (7 to 8) brush 315 and thence to `ground through the left-hand contacts ot com 31? associated with the sequence switch (not shown) of the final selector switch 350. This locking' circuit lfor relay 301 is maintained until the sequence switch of the final ulljv set forth in the application ot ll. H. Mills hereinhetore referred to,

tolll wing nuits selection and the ener- .ition ot counting relay 5112, the sender ence switch advanced to position 15.

't semence sw'tch Sil? in position 15, the

switch` cans ot which are illust ai ithin the dotted rectangle, Fig. 5, is out ot to 13, opening the stv traced locking circnit ot relay Y i at the contact ot cam 565. Relay 400. nifin tleenergizing, rcconnects the winding' ot i'ni'tilse rclg't'vY with the calling' line incr the impulse leads and Q35.

:an on "i" selections, is completed :1nd the scfinence switch associated with the 1'; al selector switch leaves position 81/2. the ,i'eviooslj; traced circuit ot relay 301 is opened at the lower cont act ot' cam 310 and relay 301 in the well-known manner causes he advance ot thi` sequence switch associitc-d with the incoming selector 300 ont ot position tl into position il. The winding` of relay 301 is now connected in series with the winding;- ot the overflow relay 531 and st' ig relay 530 at the ottice sender and t now flor-:s in such a direction h the windings ot' relay 531 as to energization. This circuit may he from battery through the right-hand winding? ot relaiv 301, the lower contacts otl in 31T` resistance element 309, the lower act ot cani 303. thence over the circuit nonsly traced through the windings of .ndcr stepping; relay 530 and polarized ferilli-w rclav 531 and returning' over contlci tor $200. the upper contact; ot cam 305, i ance element 304-, conductor 303v` the lcts ot cani 311 and thence to lc'rounil ihi'iwncli the contacts of cani 318.

'lze cnei'gizfation ot' reloj: 301 in the ciry' traced advances the sequence selector into posi- .:th in the atoreion. rthe encrgization ot stepl l0 closes a circuit tor the No. 0 cutanee relay 541 which may he traced 'cfnn hatten", through the winding of: relay he inct'nninjf left:`L lt), the contact ot cani 550 (15). f l in ice t ground at the z 'mature and (crew it' tipping relay,Y tot), Counting@r leo relay 53() becomes deenergized, the No. 0 counting relay -12 becomes energized closing at its armature and front contact a circuit for advancing the sender sequence switch 527 out of position into position 16. Relay 531 upon energizing in the previously traced circuit closes a circuit for the advance relay 541-5, which may be traced from battery through the winding of relay 35175 and thence to ground at the armature and contact of relay 5?. Relay 545 upon energizing closes u locking circuit for itself extending through its winding, left-hand armature and front contact and thence to ground through wiper 510 of switch Thi. its riglt-hand arniature and front contact rciay .lj-t5 opens thc shunt around resistance element 5:71, thereby decreasing the current fiowing over conductor 544 and through the ,vinding ot marginal relay 261 to such an extent that relay 261 thereupon becomes deeuergized and opens the circuit ot rele-.y which thereupon deenergizes and advances sequence switch 200 out of position 10 and into position 11. A circuit is now established extending through the leftland winding of relay 228 at the district selector and the winding of sender stepping relay 530 for controlling the sequence switch 2000'1l the district selector' in its talking selection movement. This circuit may be traced through the lett-hand winding of Ielay 22S. the lower left-hand contact of cam 210 (11), the upper left-hand Contact of cani 210 (11 to It). conductor 262. the outer right-hand armature and front contact of relay 2530, wiper 23T of switch SF conductor the armature and back contact of relay the winding` ot sender stepping relay 530. the winding of relay 531. the armature and bacl: contact of relay 532 and thence through the lower contact of cam (16) and resistance element 534. to ground. Relay 228 upon energizing` closes a circuit as previously traced for driving sequence switcl 200 out of position 11 and into position 15. unless this circuit is interrupted at the` armature contacts of relay 228 prior to the sequence switch reaching position 15. frs soon as sequence switch 200 leaves position 11. relays 230 and 2141 are maintained energized over a circuit which may be traced from battery through the winding' of stepping' magnet 22) of switch SF, the windings ot relays 286 and 241 in parallel, the lower contact of cam 214 (11 to 14), the righthand armature and front contact of relay 2111. the upper right-hand contact of cani 215 (Il to 14). the outer right-hand armature and front contact of relay 228 and thence to ground through the lower contacts of cani 216.

During the rotation ot sequence switch 200 from position 11 and into position 15. an intermittent ground is connected to the lil.

fundamental circuit extending through the windings ot' relays 530 and 228 between the windings ot these two relays in such a unanv ner as to hold the relay energized and to intermittently shunt out relay 530. This shunt circuit may be traced from battery through the left-hand winding. lett-hand armature and front contact of relay 228 and thence to ground through the left-hand contacts of cam 216 and is closed in position 1%, i258, 13s/8 and 141/2.

ll'ith the Sender sequence switch in position 16 and sender stepping relay 53() energized and assuming that the code which the calling subscriber has set up has so prepared the circuits of the sender as to prepare a circuit for the No. (l counting relay 5-11. the No. O counting relay 542 will beconie energized in series with relay .-ll up on the tirst deenergization ot stepping relay 53() when the sequence switch 20() ot the district selector is passing through position 1 and the previously traced circuit will be established for advancingsequence switch 52T out of position 16 into position 1. Upon the energization of counting relay 542, relay 532 energizes in parallel therewith and at its armature and back contactopens the previously traced circuit extending through the windings ot sender stepping relay 53() and the windingl of relay 22S. Relay 22S upon deencrgizing opens the previously traced circuit extending through the magnet winding ot' sequence switch 200 for arrest ingl scip-.ence switch 200 in position 12.

lilith the sequence switch of the district selector in position 12 and the squence switch of the incoming selector in position l0. a circuit is established for relay 301 of the incomingl selector switch which may be traced from battery through the right-hand winding` of relay 301, the right-hand contacts ot' cam 302. conductor 3 3. resistance element 304, the upper contact of cam 805, conductor $06, bank terminal 25T and wiper of the district selector switch, the left-hand contacts of cani 220. the upper right-hand windine,` of repeating coil 265, the lower contacts of cani 221, the windings of polarized relay 266. the upper contacts of cani the lower right-hand windingl of repeating coil 265. the upper contacts of cam 219. brush and bank terminal 256 of the district selector', conductor 307, the lower Contact of caux B08, resistance element 309 and thence to ground at the lower contact of cam 310. Relay 301 energizes in this circuit, but the current flowingl in the circuit is not in such a direction as to cause the energization of polarized relay 266. In the inaner fully set forth in the aforesaid application, relay 301 functions to initiate the application of ringing current to `the called subscribers line 13. As soon as the called subscriber responds, the application of ringing current is arrestel and the sequence switch ot the incoming selector moves into the talking position 1G and a circuit is thereupon established tor the supervisory relay 319, which may he traced from the non-grounded pole ot battery through the loyver right-hand Winding ot repeating coil 320, the Winding of relay 319, the upper contact ot' cam 314, brush 315, the upper contacts of cam 316, brush 321, terminal $22, thence over the called subscribers line loop, terminal 323, brush 2321. the lower contact of cani 312 and thence to ground through the upper right-hand Winding ot repeating coil 320. Relay 319 upon energizating in this circuit connects the terminals ot central station battery to the windings of the polarized relay 266 at the district selector in such u manner as to cause the energization ot lay 206. rl`he circuit over which relay 2136 is energized may be traced from the nongroundcd pole ot central station battery. through the upper contact ot' cam 310 (11 to 1(5), resistance element 309. the upper contacts of cani 31T (11 to 16), the loo'er lett-hand Winding of repeating coil 32o, the upper contact ot cam $308 ([11 to 1(3)` conductor 307, bank terminal 256 and brush S, thence over the circuit previously tracedthrough the Winding of polarized relay 2Go. brush 25S). bank terminal 257, conductor 80o, thc loyver contact ot cam 805 (11 to 1(3), the upper lett-hand winding of repeatingl coil S20. resistance element 304, conductor S and thence to ground at the armature and Yl'ront contactot relay 319,

lelay 266 upon energizing in this circuit closes a circuit for relay 26T as soon as cam 268 has rotated to such a position as to close, cani spring 269. This circuit may be traced troni battery, through the contact ot cani spring 269. the winding ot' relay 25T. the lett-hand contacts ot cam 21T. the contact oi polarized relay 26o and thence to groui'id at the right-hand contact ot cam 20). Vclay 267 upon energizing closes a locking circuit tor itselt` troni battery. through its righthand armature and trout contact and thence to ground oi'er the circuit previously traced independently ot cani spring contart 2W. s soon as cam 2th rotates to such a position as to open the spring contact 2th) and close spring contact 270, a cir-cuit is established tor relay 261 which may he traced trom lratteryY through the winding ot relay 2rd. the letthand armature and trout contact of relay 26T and thence to ground at spring contact 270. Relay 261 upon energizing closes a locking circuit for it sell" independent ot cam springl contact 270 which may be traced from battery through the Winding` of relay 261, the lett-hand contact of cam 218 (12 to 18), thence to ground through the right-hand armature and front contact of relay 261. At its left-hand armature and trout contact.

relay 261 prepares a charging circuit which is eti'eetive to charge a call against the calling` subscriber following the termination ol the conversation and the advancement ot sequence switch 20() into position 17. )Vith sequence syvitch 200 in position 12 tor talking, talking current is supplied to the callingl subscriber over a circuit which may be traced Atrom the non-grounded pole of central ottico battery, through the lower lett-hand Winding of repeating' coil 265, the upper contact ot cam 213, the Winding et supervisory relay 231, conductor 116. wiper 111, the innermost lovfer armature and front contact ot' relay 102, conductor 10?). thence over the subscribcr`s line loop, conductor 10i, the upper armature and trent contact ot' relay 102, wiper 113, conductor 117. the loyver right-h d contact of cam 212 and thence to the ,unded pole of battery through the upper lett-hand winding ot repeatingI coil 2%35. Reliy 2,

energizcs in this ein it and at its armature and front contact clo, s a locking circuit to maintain relay 22T energized, which may lfe traced from battery. through the lett-hand windingl ot relay 22T. the armature and trout contact ot relay 2? and thence to ground at the right-hand arn'iatnre and trout contact ot relay 22T. The called subscriber receives talking current over the circuit previously traced, through the right-hand Winding ol` repeating coil 32() and the calling and called subscribers are now connected over a talking circuit indicated in the drawings hy the heavy conductors.

During the functioning ot the olicc sender. the sequence switch. certain of the cams ot' which are shown in the dotted rectangle in Fig. 5, was positioned in position t) in the manner fully set forth in the aforesaid application ot E. H. lills and at the contact of cam a circuit was closed for advancing the time measure switch TM into position 1o, this circuit extending trom battery through the winding ot stepping magnet .302. yvipcr S, terminals ot' the bank with which thi- Wiper is associated aud thence to ground at cam 552, and the time measure switch TM' remains in position lt until the sender has fully functioned. lfolloning` thc completion ot the dialing ot' the seven digits ot' the dcsired number, the register steering switch RS is arrested in position T and a circuit established over wiper 523 and bank terminal 554 for advancing the monitoring switch M out ot' position 7 through the energization of relay 410. The circuit t'or relay 410 may be traced from battery through the righthand Winding ot relay 410, yviper 117, the No. 7 of the terminal ot the bank with which this Wiper is in engagement, conductor 428, bank contact 5.71, wiper 523 and thence to ground at the lett-hand armature and front contact of relay 51". Upon the energization et relay 410, a circuit is established tor step- 1 llt) ping magnet 418 irhich may be traced from battery through the winding of magnet 413, the armature and contact ot magnet 418, the right-hand armature and trout contact ot relay 410 and thence to ground as previously traced at the lett-hand armature and trout contact ot relay 517. Magnet 413 advances the wipers ot' switch M until wiper 4127 leaves the No. 3 terminal ot the bank when relay 510 deenergizes and opens the circuit ot magnet 418. A new stepping circuit for magnet M is now established t'rom battery, through the winding ot" magnet 413, the right-hand armature and back contact ot relay 410, the slow interrupter 419. the inner lett-hand ar mature and back contact ot relay 420, the No. 9 terminal of the bank with `which Wiper 477 is in enga, );ement` wiper 47T, the inner lett-hand armature and back contact ot relay 410 and thence to ground at the intermediate right-hand armature and Ytrout contact ot relay 405. Under the inllueuce ot interrupter 419, the switch M is :ulvanccd into position 11.

As the Wipers of the switch M pass through positions 9 and 10. a circuit is established Vtor relay 400 which may be traced from battery on conductor 411, through the winding ot relay 429, the winding ot relay 400, the outer left-hand armature and front contact ot relay 416, the Nos. 9 and 10 terminals of the bank with which Wiper 423 engages, Wiper 423, the outer right-hand armature and back contact of relay 410 and thence to ground at the intermediate right-hand armature and Vtrout contact ot relay 405. Relay 400 upon energizingl in this circuit closes a lockingl circuit At'or itself independent of wiper 423 which may be traced from battery on conductor 411, through the Winding of relay 429. winding ot' relay 400. the inner righthauil armature and 'trout contact of relay 400, conductor 430, the contacts of sequence switch cam 565, thence to ground at the armature and 'front contact of relay 501.

.\t the back contact ot' its outer righthand and outer left-hand armatures, relay 400 opens the circuit previously traced eX- tending from the subscribers line through the windings et' register stepping relay 512 and retardation coil 516 and connects the Lubscriber"s line `.Vith the windings ot mar ginal differential relays 414 and 431. The disconnection of the winding of relay 512 trom the snbscribers line loop does not cause the release ot relay 512, since this relay is maintained energized over a locking circuit which may he traced trom battery through the winding of relay 512. conductor 513. the inner left-hand armature and front contact of relay 400, conductor 432 and thence to ground at the lett-hand armature and front contact of relay 517.v The energizing traced from the source 460 ot negative current, which is preferably ot 110 Volts potential through the left-hand armature and tront contact of relay 429, the inner letthand armature and back contact of relay 412, the outer right-hand armature and back contact of relay 415, the left-hand windings of marginal ditferential relays 414 and 431, bank terminals Nos. 9, 10 and 11 to Which the Wiper 406 has access, Wiper 406, the outer right-hand armature and front contact of relay 400, the outer right-hand armature and back contact of relay 401, conductor 402, thence as previously traced to the subscrilwrs line and returning over conductor 403. the outer left-hand armature and back contact ot' relay 401, the outer lett-hand armature and front contact of relay 400, wiper 433 and the Nos. 9, 10 and 11 bank terminals to which this wiper has access, the right-hand windings of relays 431 and 41.4, the inner lett-hand armature and back contact of relay 415 and thence to ground at the outer right-hand armature and front contact of relay 405. Relays 414 and 431 being differentially Wound do not energize in this circuit.

lt will be assumed that the calling subscriber deposited the required coin or token in his coin device either before dialing the number ot the called line or immediately following the dialing of the number and that, therefore, at the time the dialing Was completed and the monitoring switch M reached position 9, an effective energizing circuit for relay 414 Was established. This circuit may be traced from the source 460 of negative current, through the left-hand armature and front contact of relay 429, the inner left-hand armature and back contact of relay 412, the outer right-hand armature and back contact of relay 415, the lefthand windings of relays 414 and 431, wiper 406, the outer right-hand armature and trout contact of relay 400, the outer righthand armature and back contact of relay 401, conductor 402, the inner left-hand ai mature and front contact of relay 505, conductor 515, Wiper 232, the outer left-hand armature and front contact of relay 230 conductor 233, the lower left-hand contact ot cam 212. conductor 117, Wiper 113, the upper armature and front contact ot relay 102. conductor 104 the Winding of coin collection magnet 126 and thence to ground through the contacts 127 which were operated upon the deposit of the coin. Relay 414 onergizes in series with the Winding of magnet 126, 'but relay 431 being marginally wound does not energize and polarized magnet 120 does not receive suilicient current through the Wii'iding of relays 414 and 431 to energize at this tiine.- Relay 414 upon energizing opens the previously traced lockcircuit l'or relays-414 and 431 may now being circuit of'relay 409, and relay 409 upon deenergizing opens the circuit of relay 416 the circuit of the magnet 418.

which, in turn, opens the circuit of relay 529, so that when the sender sequence switch 527 reaches position 14 preparatory to controlling units selection, relay 529 will not become energized to hold the fundamental circuit open at its armature and Contact. If the calling subscriber had not deposited the coin. then relay 414 would not then energize as previously described and when sequence switch 527 of the sender reached position 13, a circuit would have been established for relay 529 which may be traced from battery through the contact of cam (13 to 14), relay 529 conductor 556 and thence to ground at the right-hand armature and front contact of relay 416.

lf the calling subscriber has not deposited the coin at the time switch M reaches position 11, the coin lamp 434 is caused to flicker over a circuit which may be traced trom battery through the lamp 484, the outer letthand armature and back contact of relay 412, the inner lett-hand armature and trout contact of relay 416, interrupter 435, the normally closed contacts associated with the inner right-hand armature ot relay 415, bank terminal 436, wiper 42?), the outer letthand armature and back contact of relay 311.1410 and thence to ground at the intermediate right-hand armature and front contact ot relay 405. The flickering of lamp 434 signals the monitoring` operator that either the calling subscriber has deposited no coin or that the coin is stuck in the coin chute and the monitoring operator may then take such steps as are necessary to obtain the deposit ot the coin, or the clearing of the trouble. During the operation of coin lamp 434. the pilot lamp 424 is operated over a circuit which may be traced through lamp 424. bank terminal 487, wiper 477, the inner leftlrand armature and back contact of relay 410 and thence to ground at the intermediate right-hand armature and front contact of relay 405.

1t when the time measure switch M reaches position 9 the calling subscriber has properly deposited the coin and consequentlycthe cire-nits of relays 409 and 416 are open due to the energization ot relay 414, a circuit is closed for advancing the. time measure switch-.'M from position 9 into position 'l5 through the operation ot relay 410. rlhe circuit'ot relay 41() may bei-traced from battery through the right-hand Winding of the relay, Wiper 417 and bank terminals 9 to 14 with which-it contacts during its yadvancement,v and thence to groundl at the righthand arinaturegand back.r contact of relay 416. Relay- 410=ufpon energizing closes 1the previously traced., circuit for the stepping magnet 4:18, willich.;'circuitl is;;1na-i-.n.tained, imlllwpef i123.' lefviesf terminal 14l of'. itsA 'f bangavhenretay'=41,0 deen-ergizes and opens:

In position 15, relay 410 is again energized over wiper 417, the inner left-hand armature and back contact of relay 415 to ground at the outer right-hand armature and front contact ot' relay 405 and the previously traced circuit is again established through stepplngr magnet 418 for advancing the switch M into position 18. Relay 410 deenergizes as soon as the switch M reaches position 18, and closes a new circuit for advancing the switch M into position 21, which circuit may be traced from battery through the winding of magnet 418, the right-hand armature and back contact ot relay 410, interrupter 419, the inner left-hand armature and back contact of relay 420, the bank contacts with which wiper 477 is associated, wiper 477, the inner letthand armature and back contact ot relay 410 and thence to ground at the intern'iediate right-hand armature and trout contact ot relay 405.

lf at the time the wipers ot the time measure switch M reach position 21. the sender has not functioned to set up the desired connection, the lamp 421 is lickered to denote a stuck sender. The circuit ot' lamp 421 may be traced trom battery through the lamp, the inner left-hand armature and back contact of relay 416, interrupter 435, bank terminal 438, wiper 423, the outer lefthand armature and back contact of relay 410 and thence to ground at the intermediate right-hand armature and front contact of relay 405.

The pilot lamp 424 is also lighted at this time over a` circuit which may be traced through. conductor 439, wiper 477, and thence to ground at the intermediate righthand armature and front Contact of relay 405. [Tniler the assumption that the establishment of the connection proceeded without interruption in the manner hereinbefore described, as soon following units selection as the sequence switch ot' the district selector advances out. of position 10, the impulse leads 233 and 235 which up to the time sequence switch 200 leaves position 10i/2 are connected with the winding of register stepping relay 512 and the winding of retarolation coil 516, are disconnected trom the district selector trunk conductors 116 and 117 at the contacts of, sequence switch cams 212 and 213. Upon the opening` ot the circuit over impulse leads 283 and 285, relay 512 deenergizes, opening the circuit of slow releasing relay 517,` which, upon deenergizing, closes a circuit extending from ground through the armature and back contact of relay 512, the right-hand*armature and back contact'otrelay 517. resto-ring` segment 557 oftheswitclrRS; wiper 524 and thence to battery through ,Y the. armature contact`-` and winding or" stepping magnet 522. Under the nttueace cit-magnet 522, the switchl RS is restored to its normal position. Following the restoration of the switch RS, the code and numerical registers of the sender are restored and all the circuits ot the sender are placed in their normal position so that the sender may he employed in the estalilishlncnt ot other connections.

1176760.20 of Sca/ler.

Upon the completion of talkincr selection and the deenergization ot' relay 228 of the district selector switch. relays E330 and 234 hccomc deenern'ized, since their locking' cir cuit is now opened at the outer right-hand armature and tront contact ot relay and I'elay 2530 upon deencrg'izing. opens the previously traced circuit ot relay 501. ftelay 501 upon deenergizino closes a restoring circuit' tor the time measure switch TM. which may he traced from battery through the winding ot stepping.r magnet 502. the armature and hack contact of this l'nae'nct. wiper the terminals of restoring hank 555) and thence to ground at the armature and hack contact ot relay 501. Under the influence of magnet 502. the time measure switch is restored to normal position. Upon the deenergization of relay 501. the holding` circuits of relays 505 and 405 are opened at the armature and front. contact ot relay 501 and these relays thereupon hccome deenerglized. The deenergiI/.ation of relay 505 disconnects the impulse leads 514 and 515 and the deenergg'ization ot relay 105 closes a circuit for restoring the monitoring` time switch M into its normal position.

lpon the dccne1';'iZation ot' relay JC05. a circuit is established tor relay 410 extending' from hattery through the right-hand winding' ot relay 410. the oti'-nornuil ter` niinals ot the restoringl henk 440. wiper 441-1 and thence to ground at the outer left-hand armature and hach contact of relay Relay j10 upon energizing cstahlishes a circuit tor the steppingr magnet 41S extending; trom hattcry through the winding otI nl:

ret 51%. the armature and hack contact et 7'crnz'fnat'oa 12,1" coreTrentin Scf'fcrc of on idle sender.

Upon the termination ot the conversation. 1coth the ca led and calling Subscribers rest-ore their respective receivers to their switchhooks. At this time. relay 261 is energized as previously described. Upon the restoration of the calling suhscriliiers receiver to its switchhook. supervisory relay 234 deenergrizes, opening the holding circuit of relay 227 and since the circuit through the right-hand winding; of relay is open at this time. the sender having heen `disassociated troni the district selector. relay 92T decnerrif/.es closing a circuit tor driving' sequence switch 200 out of position 12 and into position 1G. this circuit extendine' Yfrom battery through the winding of sequence switch magnet i200. the lower left-hand contact ol cam Q00 (1Q to 1T), the left-hand contacts oi" cam Q93 and thence to Iground at the normal contacts associated 'ith the richt-hand armature of relay 22T. .\t its let`1-hand armature. relayY Q27 opens the previously traced lockingr circuit for relay 220 extending' over the upper contact o lE cam Q03 and cstahlislu,4 a new locking' circuit therefor. which may he traced through thc left -hand winding o l relay 220. the normal contacts associated with the lctt'hand armature of relay the lower right-hand coir tact ot cam 2t il and thence over the sleeve conductor '1S and to ,ground through the winding ot' relay 10Q as previously described. its sequence switch 200 reaches position 10. a circuit' is closed for relay which may lie traced from battery. through the right-hand winding of relay 228. the upper contacts ot cain 204. the right-hand armature and front Contact ot' relay 226. the upper riOht-hand and lower lett-hand contacts of sequence switch cani 22? and thence to ground at the normal contact associated with the right-hand armature oi'i relay 227. l-elav upon energizing, closes a circuit tor driving' sequence switch 200 out ot position 10 and into posiion 1T. which circuit may lee traced from hattery throunh the man net winding ot sequence switch Q00. the lower right-hand contact of cani Q00 (10). the inucr right-hand armature and trout contrrt ot relay and thence to .ground at the right-hand contact of cani Q07. Relay :'QS upon energizing' estchlishes a locking circuit tor is'el't' extending! through itsA lctthanfl windiniz'. its le'thand armature and trout contact. the lower right-hand contact of cani 210. th.n lower lett-hand contact of cani 211 (l0 to Ul. the outer lett-hand trre and Vfront contact ot relay Wiper and therce to crcmndV 'it the contact of the honi: with which wiper 231 is then in meiner-mnt. it the sender associated with the inultii'zles upon which the wipers of the sander finder Si? are then resting is at the time einploved. Vhen sequence switch 200 reaches position 17. a circuit is established for the stepping magnet 229 of the switch SF extending' trom battery1 through the armature contacts and Winding ot magnet 220. the lower contact of cam 20S (1025/1 to 17). the inner right-hand armature and trent contact of relay 228 and thence to ground at the right-hand contact ist 

